diff --git a/airflow/config_templates/config.yml b/airflow/config_templates/config.yml
index f29a70216c6cd..36438dec853b1 100644
--- a/airflow/config_templates/config.yml
+++ b/airflow/config_templates/config.yml
@@ -1391,24 +1391,6 @@ api:
       example: ~
       version_added: 2.0.0
       default: "100"
-    google_oauth2_audience:
-      description: The intended audience for JWT token credentials used for authorization.
-        This value must match on the client and server sides.
-        If empty, audience will not be tested.
-      type: string
-      version_added: 2.0.0
-      example: project-id-random-value.apps.googleusercontent.com
-      default: ""
-    google_key_path:
-      description: |
-        Path to Google Cloud Service Account key file (JSON). If omitted, authorization based on
-        `the Application Default Credentials
-        <https://cloud.google.com/docs/authentication/production#finding_credentials_automatically>`__ will
-        be used.
-      type: string
-      version_added: 2.0.0
-      example: /files/service-account-json
-      default: ""
     access_control_allow_headers:
       description: |
         Used in response to a preflight request to indicate which HTTP
diff --git a/providers/google/docs/api-auth-backend/google-openid.rst b/providers/google/docs/api-auth-backend/google-openid.rst
index 303e81869d13f..03885876cbea9 100644
--- a/providers/google/docs/api-auth-backend/google-openid.rst
+++ b/providers/google/docs/api-auth-backend/google-openid.rst
@@ -18,6 +18,8 @@
 Google OpenID authentication
 ''''''''''''''''''''''''''''
 
+.. note:: This authentication mechanism only works for Airflow 2.x
+
 You can also configure
 `Google OpenID <https://developers.google.com/identity/protocols/oauth2/openid-connect>`__
 for authentication. To enable it, set the following option in the configuration:
diff --git a/providers/google/src/airflow/providers/google/common/auth_backend/google_openid.py b/providers/google/src/airflow/providers/google/common/auth_backend/google_openid.py
index 4a3f45fa4a3a8..e18e90af6a8a0 100644
--- a/providers/google/src/airflow/providers/google/common/auth_backend/google_openid.py
+++ b/providers/google/src/airflow/providers/google/common/auth_backend/google_openid.py
@@ -32,12 +32,16 @@
 from google.oauth2 import service_account
 
 from airflow.configuration import conf
+from airflow.exceptions import AirflowProviderDeprecationWarning
+from airflow.providers.google.common.deprecated import deprecated
 from airflow.providers.google.common.utils.id_token_credentials import get_default_id_token_credentials
 
 log = logging.getLogger(__name__)
 
 _GOOGLE_ISSUERS = ("accounts.google.com", "https://accounts.google.com")
-AUDIENCE = conf.get("api", "google_oauth2_audience")
+AUDIENCE = conf.get(
+    "api", "google_oauth2_audience", fallback="project-id-random-value.apps.googleusercontent.com"
+)
 
 
 def create_client_session():
@@ -52,6 +56,11 @@ def create_client_session():
     return AuthorizedSession(credentials=id_token_credentials)
 
 
+@deprecated(
+    planned_removal_release="apache-airflow-providers-google==15.0.0",
+    reason="Auth backends are not supported on Airflow 3, and this entire module will be removed",
+    category=AirflowProviderDeprecationWarning,
+)
 def init_app(_):
     """Initialize authentication."""